A common procedure in the abrading, polishing and finishing of irregularly shaped objects, for example, stones and minerals in lapidary practice, both professional and amateur, is to tumble the objects with a suitable abrasive composition in the barrel of a tumbling apparatus. U.S. Pat. No. 4,045,918 to Freedman discloses an abrading and polishing tumbler apparatus having one or two barrels in which in which the tumbler barrel is concurrently rotated and rocked and includes an internally ribbed barrel having a separable closure cap at one end. This apparatus has a fairly complex drive mechanism and is noisy when being operated as the stones in the tumbler clang against the side wall of the tumbler as the tumbler is rotated.
U.S. Pat. No. 6,254,466 B1 discloses a tumbler for abrading small parts and rocks in which the objects are placed into a cylindrical drum or barrel along with a grinding medium and liquid. This patent teaches that the barrel can be made of rubber. But, like Freedman this patent also does not mention noise as being a problem, perhaps because the rocks are in a liquid as they are being ground.
Rock tumblers have been made is several sizes ranging from those having barrels that are several meters in diameter for industrial use to table top tumblers which are about 10 to 15 centimeters in diameter. Smaller rock tumblers are available in some toy stores and craft stores for use by children. These products are often used indoors where noise from rocks clanging in the tumbler can be annoying. Consequently, there is a need for a very quiet rock tumbler that can be used by children indoors.